GB427044A - Improvements in or relating to machines of the type having a working tool or knife for treating hides, skins, leather and the like, and to means for grinding such tools or knives - Google Patents

Abstract

427,044. Grinding machine cutters in situ ; controlling reversing - gearing. TURNER TANNING MACHINERY CO., Ltd., and SCHETTLER, G. A., Railway Foundry, Bramley, near Leeds. Nov. 1, 1933, No. 30361. [Class 60] [See also Group XXIV] The grinding wheel 1 for sharpening the rotary cylindrical cutter 8 of a leather-treating machine is carried on a traversing saddle having a base 3 mounted on an inclined slide 5 and guided by a single V - shaped guide 4 at the upper edge, the slide carrying a traverse and reverse mechanism, providing for a time interval between the end of each traverse and the beginning of the return movement and also for automatically stopping the traverse with the grinding wheel at the end of its stroke and clear of the cutter, and the grinding wheel is driven directly from a pulley or equivalent on the saddle by means of a belt or the like. The inclination of the slide 5 causes the V-guide 4 always to keep in contact with the V-way on the slide, thus avoiding backlash due to wear. In the machine shown the slide 5 is pressed by weighted levers 72 against screws 70 simultaneously operated by worm gearing in order to adjust the wheel in relation to the cutter. A motor 11 mounted on the upper end of a housing 10 on the saddle drives the grinding wheel by a belt 15 and also traverses the saddle by actuating, through reversing mechanism, a pinion 18 which engages a rack 17 arranged in a recess in the slide 5. The reversing mechanism comprises bevel wheels 29, 30 mounted on a shaft 31 driven through worm and wheel gearing from the motor, these wheels gearing with a driving bevel 24 on the shaft 19 of the pinion 18 and being alternatively clutched to the shaft 31 by a sliding clutch 28 for traverse in one direction or the other. The clutch is shifted by a fork 32, Fig. 6, carried by an arm 33 freely pivoted on a shaft 34, and moved by an arm 35 secured to the same shaft and carrying spaced lugs 36 straddling the arm 33 and allowing lost motion between the two arms. A spring-pressed plunger 38 acting on a roller mounted on the arm 35 urges it to one side or other of the central position. The reversal of the traverse at the ends of the stroke is brought about by an arm 45, Fig. 4, on the lower end of the shaft 34 connected by a link 46 to an arm 48 which engages adjustable stops at the ends of the stroke. To provide a time interval between the strokes, the wheel 24 is rotatable on its shaft, and is formed with projections engaging, with a degree of lost motion, in peripheral recesses 95 in a disc secured to the shaft. A spring-pressed bolt 41, Fig. 8, engages a slot 42 in the end of the arm 33 to hold it in the neutral position to stop the traverse of the carriage. A wedge 57 operated by the starting handle 59 engages a roller 61 mounted in a slot 58 in the bolt 41 and moves the bolt to the position shown to release the arm 33 and also to close the switch 51 controlling the motor circuit. When the starting handle is operated to withdraw the wedge 57, the grinding operation continues until the end of the traverse on which the wheel is engaged at the time is completed, but when the reversal movement begins the bolt 41 falls into the slot 42 and retains the arm 33 in the neutral position. At the same time the movement of the bolt opens the switch 51 of the motor circuit. The traverse of the grinding wheel may be reversed at any point by a tool applied to the projecting upper end 34a of the rock shaft 34. The mains switch 63, Fig. 1, controlling the motor circuit is operatively connected to the belt-striking gear or other means for starting and stopping the rotation of the cutter 8, so that the grinding mechanism can be operated only when the cutter is revolving. The grinding wheel spindle 9, Fig. 4, is secured at one end only, so that the wheel 1 may be removed or replaced on the hub 87 merely by removing a clamping- nut 89 and withdrawing a poppet or screw 91 which supports the free end of the spindle.